... ring for filtering waste gas: 1.material:PE,PP,RPP,PVC,CPVC,PVDF 2.diameter:16mm ... heat resistant and chemical corrosion resistant plastics, including polyethylene (PE), polypropylene (PP), reinforced polypropylene (RPP), polyvinyl chloride ( ... it is widely used in the packing towers in petroleum industry, chemical industry, alkali-Chloride industry, coal gas industry and environmental protection, etc ...